Find the pH of a 0.600 M solution of methylamine CH3NH2. Kb= 4.4 x 10^-4

Answers

Answer 1
Since methylamine (CH3NH2) is a weak base, the major species in solution are CH3NH2 and H2O.
Both are bases; however, since water can be neglected as a source of OH-, the dominant equilibrium is:
CH3NH2(aq) + H2O(l) = CH3NH3+(aq) + OH-(aq)
and



The concentrations are as follows:



[OH-] = [CH3NH3+] = x
[CH3NH2] = 1.0 - x
Then,




Assume that 1 >> x, then:
(1.0 - x) = 1.0
Kb = x2 / 1.0
x2 = Kb
x = (Kb)0.5 = (4.38×10-4)0.5 = 0.0209
x= [OH-] = 0.0209 M

We can convert between [OH-] and pOH using the following equations:
pOH = - log[OH-]
pOH = - log(0.0209) = 1.68
pOH = 1.68

For any aqueous solution at 25∘C:
pH + pOH = 14
pH = 14 - pOH = 14 - 1.68 = 12.32
pH = 12.32

Answer: pH = 12.32

Related Questions

Write a net ionic equation for the reaction that occurs when excess hydroiodic acid and chromium(II) carbonate (s) are combined.

Answers

Step 1: Write the balanced "molecular equation:

[tex]2HI(aq) + CrCO₃ (s) → CrI₂ (s) + H₂O(l) + CO₂(g)[/tex]

Step 2: Carbon dioxide and water are written in molecular form. Consult the solubility and net ionic equation rules on the information page to determine which of the other substances will dissociate:

[tex]2HI(aq) + CrCo₃ (s) → Crl₂ (s) +H₂O(l)+CO₂(g)[/tex]

yes no yes

Step 3: Dissociate all soluble salts, strong acids, and strong bases (except calcium hydroxide), Leave together all "not soluble" salts and weak acids or bases:

[tex] {2H₂O}^{ + } (aq) + {2I}^{ - } (aq) + CrCO₃ (s)→ {Cr}^{2 + } (aq) + {2I}^{ - }(aq) + 3H₂O(l) + CO₂(g)[/tex]

Step 4: Cross out "spectator lons that appear on both sides of the reaction (these lons do not participate in the chemistry) and rewrite the "net" reaction using the smallest possible coefficients:

[tex] {2H₂O}^{ + } (aq) + CrCO₃ (s) →3H₂O + CO₂ + {Cr}^{2 + } [/tex]

A student observes the phenomenon where a straw has a different appearance when placed in water. Once this was noted by the student, they then immediately thought about why they have been unable to successfully catch fish when spearing them in the water. Relate these two phenomenon and select ALL statements that apply to the phenomena described here.
A)The water distorts the image of the fish so that its image is inverted.
B)The student is not aiming correctly due to refraction of the fish in the water.
C)The water magnifies the image, making the target fish look bigger than it actually is.
D)The light waves travel at a different speed in water and make the fish appear farther away.
E)The diffraction of the light around objects flips the image from left to right, making aiming for fish more of a challenge.

Answers are B and D

Answers

Answer:

b, and d

Explanation:

if the student did not aim correctly, and for d if the light waves travelled differently

Where does runoff end up?
a)ponds
b)streams
c)rivers
d)all of the above

Answers

Answer:

All of the above :D

Explanation:

When rain falls, if it doesn't get absorbed by the dirt, it will go into streams, rivers, and ponds. That is actually how flooding is caused!!! :D

Have an amazing day!!

Please rate and mark brainliest!!

A graphic designer has the choice to download design software on her computer and then design a logo or to use an online
version of the software to design the logo. Identify one advantage and one disadvantage of using the online software to design
the logo 2 points)

Answers

An online version is the availability of the application on the web and the internet. The online version of the logo designer is advantageous as it provides more customization choices.

What is logo designing?

A logo design is a method to create logos that represent the brand of the business corporation or any other organization, it represents the company and brand.

Online software for logo designing provides more choices for customization as more fonts, styles, graphics, colors, and effects are present in online software.

The use of online software can be disadvantageous as it can be copied. The same tool and online data can be used to create the same logo and can be harmful to the company.

Therefore, using online software for logo designing can be both advantageous and disadvantageous.

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Answer:

Explanation:first one

Which chemical symbol describes an element? C2H6 Cl2 H2O2 CuSO4

Answers

Answer:

Cl2

Explanation:

Chlorine is a diatomic element  so it is   Cl 2

 the others are MOLECULES  (made up of atoms of ELEMENTS)

Oleic acid, a component of olive oil, is 76.54% C, 12.13% H, and 11.33% 0. The
experimental value of the molar mass is 282 g/mol.
a. What is the molecular formula of oleic acid?
b. If oleic acid has a density of 0.895 g/mL, how many molecules of oleic acid
are in 3.00 mL of oleic acid?

Answers

Answer:

a) The molecular formula of oleic acid is: [tex]C_{18}H_{34}O_{2}[/tex]

b) There are 5.74 x 10^21 molecules of oleic acid in a 3.00 mL sample.

Explanation:

a)

First, let's determine the empirical formula of oleic acid from the percentage composition provided by the question:

- Assuming a 100g sample of oleic acid, the correspondent mass of C, H and O would be:

mass of C = 76.54g

mass of H = 12.13g

mass of O = 11.33g

- We must determine the number of moles contained in each of the masses determined above. For that, let's use the atomic masses of C (12.01 u), H (1.007 u) and O (15.99 u) and the following equation:

[tex]number of moles = \frac{mass of sample}{molar mass}[/tex]

number of moles of C = 76.54g / 12.01 g/mol = 6.373 mol C

number of moles of H = 12.13g / 1.007 g/mol = 12.04 mol H

number of moles of O = 11.33g / 15.99 g/mol = 0.7086 mol O

- Next, we'll try to find whole-number ratios by dividing each number of moles obtained by the smallest value obtained (0.7086):

C = 6.373 / 0.7086 = 8.994 ≅ 9

H = 12.04 / 0.7086 = 16.99 ≅ 17

O = 0.7086 / 0.7086 = 1.000

- Now, we can write the empirical formula of oleic acid as: [tex]C_{9}H_{17}O[/tex]

Now that we have the empirical formula for oleic acid (C9H17O), let's check its molar mass and compare it to the experimental value provided by the question (282 g/mol):

molar mass (C9H17O) = 9 * 12.01 + 17 * 1.007 + 1 * 15.99 = 141.9 g/mol

Note that the molar mass obtained from the empirical formula (141.9 g/mol) and the experimental molar mass (282 g/mol) are different, thus we need to find an integer multiple to determine the molecular formula (keep in mind that molecular formulas always present kind and number of atoms of each element present in the molecular compound, while the empirical formula presents the smallest coefficients for each atom).

Molecular formula = n × Empirical formula

This integer multiple, n, can  be obtained by dividing the molar mass,  MM , of the compound by the empirical formula mass,  EFM  (the molar mass represented by the empirical formula):

n = MM / EFM

n = 282 / 141.9

n = 1.987 ≅ 2

Since the integer multiple is 2, we can multiply all coefficients in the empirical formula by 2 to find the molecular formula of oleic acid:

C9 H17 O x 2 = C18 H34 O2

Therefore, the molecular formula of oleic acid is: [tex]C_{18}H_{34}O_{2}[/tex]

b)

We need to calculate the amount of molecules of oleic acid in a 3.00mL sample, considering the density as 0.895 g/mL.

From the density provided, we can calculate the mass, in grams, of oleic acid contained in 3.00 mL of this compound:

1 mL ----------------------- 0.895 g oleic acid

3.00 mL ----------------- x

Solving for x, we have that there are 2.69 g of oleic acid in a 3.00 mL sample.

Next, considering the molar mass of oleic acid (282 g/mol), we can calculate the number of moles contained in 2.685g of the acid:

282 g -------------------- 1 mol oleic acid

2.69 g ----------------- y

Solving for y, we have that there are 0.00953 moles of oleic acid in a 3.00 mL sample.

Now, using the Avogadro's number (6.022 x 10^23 particles/mol), we can calculate the amount of molecules of oleic acid in the sample:

1 mol oleic acid ------------------------------- 6.022 x 10^23 molecules oleic acid

0.00953 mol oleic acid ------------------- z

Solving for z, we have that there are 5.74 x 10^21 molecules of oleic acid in a 3.00 mL sample.

When fossil fuels are burned, they release pollutants into the air. When hydrogen is burned, it produces clean water. There are limited amounts of fossil fuels that can be uncovered by digging in the Earth. Hydrogen must be produced from other materials, such as water, which requires using energy.

In order to determine whether replacing fossil fuels with hydrogen would be good for the environment, what question must be answered?

Answers

Answer: can hydrogen produce as much energy as burning fossil fuels?

Explanation:

Which of the following compounds will have the lowest molar solubility in pure water?

a-AgBrO3, Ksp = 5.38 x 10-5
b-MnCO3, Ksp = 2.24 x 10-11
c-Hgs, Ksp = 1.60 x 10-54
d-Zns, Ksp = 2.00 x 10-25
e-SrS04, Ksp = 3.44 x 10-7

Answers

Answer:

C

Explanation:

It has the lowest Ksp, so it will have the lowest Molar Solubility

Which of the following conversions is/are incorrect.

a.1 meter = 1000 millimeters
b.100 millimeters = 1 centimeter
c.500 centimeters = 0.5 meters
d. 1 kilometer = 1000 meters

C+A
B+ C
D+ C
A+B

Answers

Answer:

B + C ARE INCORRECT FROM THE ABOVE GIVEN CONVERSIONS.

How many molecules are there in a 42.3g sample of water

Answers

Answer:

This means that one mole of water molecules has a mass of 18.015g.

42.3g * 1 mole H2O/18.015g

= 2.3480 moles H2O

We are using the avogadros number to find the number of molecules of water

2.3480 H2O * 6.022*10^ 23moles/ 1mole of H2O

That's 2.3480 multiplied by 6.022*10^23 divided by 1 mole of H2O

Number of molecules = 1.4140 *10^24 molecules

What type of microorganism turns milk into yogurt?

Answers

For yogurt production, probiotic bacteria and the Streptococcus thermophilus strain work together to produce a stable balance of bacteria in the culture.

The picture shows the cubic unit cell of CaF2. How many Ca2+ ions and F- ions are present in the cubic unit cell?

Answers

The total number of Ca2+ ions and F- ions that are present in the cubic unit cell will be 4 and 8 respectively.

How to calculate the unit cell?

From the complete information, the number of Ca2+ at corners will be (8 × 1/8 = 1) and those a the center will be (6 × 1/2 = 3). Therefore, the total number of Ca2+ will be:

= 1 + 3 = 4

The total number of F- ions will be:

= 4 × 2 = 8

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what is daily product ? Any ten point​

Answers

Answer:

the interest applied on the end of day balance.

Explanation:

During complete metamorphosis, what best describes the transformation from a larva to a pupa?

The larva goes through a big change in color.
The larva might form a cocoon or a chrysalis.
The larva might hatch into an adult.
The larva sheds its skin several times.

Answers

Answer:The larva might form a cocoon or a chrysalis.

Explanation:

Aerobic decomposition of organic matter requires

A.nitrogen.

B.oxygen.

C.carbon dioxide.

D.water.

Answers

the answer to this question is b. oxygen

Answer:

Option B: Oxygen.

Explanation:

Hope this helped.

If 25.0 mL of a 2.00 M HCl solution is diluted to 2.00 L, what is the molarity of the new solution?

Answers

The molarity of a new solution that has a volume of 25.0 mL of a 2.00 M HCl solution and diluted to 2.00 L is 0.025M.

How to calculate molarity of a solution?

The molarity of a solution can be calculated using the following formula:

C1V1 = C2V2

Where;

C1 = initial concentrationC2 = final concentrationV1 = initial volumeV2 = final volume

2 × 25 = 2000 × C2

50 = 2000C2

C2 = 50 ÷ 2000

C2 = 0.025M

Therefore, the molarity of a new solution that has a volume of 25.0 mL of a 2.00 M HCl solution and diluted to 2.00 L is 0.025M.

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Which element has the highest 2nd ionization energy?
A. Be
B. C
C. Li
D. B

Answers

Answer:

The answer is c.........

The answer is C, Lithium

Why is sodium chloride not considered a molecular compound? What kind of compound is it?

Answers

Answer:

Something like table salt (NaCl) is a compound because it is made from more than one kind of element (sodium and chlorine), but it is not a molecule because the bond that holds NaCl together is an ionic bond. If you like, you can say that sodium chloride is an ionic compound.

Explanation:

How does a specific theory compare to a scientific law

Answers

Do you mean scientific theory? If so, then scientific theories and laws are principles which can be used to better understand the world and space around us.

Which of the following is an example of chemical weathering?

A. A river carrying dirt into a lake.
B. Wind carrying sand from a beach.
C. Chemicals in water dissolving minerals in rock.
D. Friction between two rock surfaces grinding away minerals.

Answers

Answer:

C

Explanation:

Answer: D. Friction between two rock surfaces grinding away minerals.

Explanation: chemical weathering involves erosion from rocks/materials

whats ur favorite type of subject in school

Answers

Answer:

MAthhh

Explanation:

Give me a brainly

Answer:

My favorite subject in school is P.E or Language arts

Explanation:

A 25.0-L balloon at 20.0 ⁰C is placed in a hot water bath at 90 ⁰C. After 15 minutes, the volume of the balloon stops expanding. What is the new volume of the balloon?

Answers

Apply Charles law

V1T2=V2T125(90)=20V225(9)=2V2225=2V2V2=225/2V2=112.5L

Wildfires displace many animals and leave behind ash and soot-covered habitats for the animals that
survive. If a wildfire
occurred in the Everglades, which insect would be the
most likely to survive
predators in an ash and soot-covered habitat? (SC.5.L. 15.1)
A. Red dragonfly
B. Green grasshopper
C. Brightly colored butterfly
D. Gray-colored speckled moth
7. A group of students is using models to explore the relationship between the shape of a bird's beak
the type of food it eats. The students design an investigation using classroom items as beaks. Each

Answers

If a wildfire occurred in the Everglades, the insect which most likely to survive predator is gray-colored speckled moth.

What are predators?

Predators are those animals which for their survival will hunt or kill another animals for the fulfilment of their food need.

If wildfire occured in the everglades region then the insect would be the most likely to survive predators in an ash and soot covered habitat is gray-colored speckled moth which is also known as darwin moth as it takes part in evolution of natural process.

Hnece the required animal is gray-colored speckled moth.

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100 points! Please help if you are able to.

Answers

Here are the balanced equations

C_2H_5OH+3O_2--->2CO_2+3H_2O+Energy2AgCl-->2Ag+Cl_2AgNO_3+Zn--->Ag+ZnNO_3

3BaCl_2+Al_2(SO_4)_3--->3BaSO_4+2AlCl_3H_2+I_2--->2HI

Done!

6.11C In 1976, the Viking I Lander was sent to Mars to analyze atmospheric gases and soil samples. The Viking I Lander was most likely a
a space probe.
b lunar module.
c space shuttle.
d natural satellite.

Answers

B lunar module :) pls Brainly?

okay this is the only way to get my answers

Answers

Answer:

Your answer is Answer thank me later :) <3

Explanation:

pls pls help me with this

Answers

Answer:

1. lava

2. caldera

3. true

4. true

5. before

What is the molarity of 4 g of NaCl in 3,800 mL of solution?

Answers

Answer:

.018 M

Explanation:

Mole weight of NaCl (from periodic chart) = 58.44 g /mole

4 g / 58.44 gm/mole = .06845 mole

.06845 mole / (3.8 liter ) = .018 M

Ethanoic acid has a pKa of 4.75. Find the pH of the solutions that results from the addition of 40.0 mL of 0.040 M NaOH to 50.0 mL of 0.075 M ethanoic acid.

Answers

Answer:

About 4.63.

Explanation:

The reaction between ethanoic acid (CH₃COOH) and sodium hydroxide (NaOH) can be described by the following net ionic equation:

[tex]\displaystyle \text{CH$_3$COOH}_\text{(aq)} + \text{OH}^-_\text{(aq)}\longrightarrow \text{CH$_3$COO}^-_\text{(aq)} + \text{H$_2$O}_\text{($\ell$)}[/tex]

40.0 mL of 0.040 M NaOH contains:
[tex]\displaystyle 40.0\text{ mL} \cdot \frac{0.040\text{ mol NaOH}}{1000\text{ mL}} = 0.0016\text{ mol NaOH}[/tex]

Because NaOH is a strong base, it dissociates completely. Hence, the amount of OH⁻ present is 0.0016 mol. Na⁺ acts as a spectator ion.

50.0 mL of 0.075 M CH₃COOH contains:
[tex]\displaystyle 50.0\text{ mL} \cdot \frac{0.075\text{ mol CH$_3$COOH}}{1000\text{ mL}} = 0.0038\text{ mol CH$_3$COOH}[/tex]

OH⁻ is the limiting reagent of the reaction. Therefore, as the reaction proceeds to completion:

The amount of OH⁻ drops to 0 mol. The amount of CH₃COOH decreases to (0.0038 - 0.0016) mol = 0.0022 mol. And the amount of CH₃COO⁻ increases to (0 + 0.0016) mol = 0.0016 mol.

Note that all species present are in a one-to-one ratio.

To find pH, we can use the Henderson-Hasselbalch equation:

[tex]\displaystyle \text{pH} = \text{p}K_a + \log\frac{[\text{Base}]}{[\text{Acid}]}[/tex]

The total volume of the solution is 40.0 mL + 50.0 mL = 90.0 mL.

Hence, find [CH₃COOH]:

[tex]\displaystyle \left[\text{CH$_3$COOH}\right] = \frac{0.0022\text{ mol}}{90.0\text{ mL}} \cdot \frac{1000\text{ mL}}{1\text{ L}} = 0.024\text{ L}[/tex]

Find [CH₃COO⁻]:
[tex]\displaystyle \left[\text{CH$_3$COO}^-\right] = \frac{0.0016\text{ mol}}{90.0\text{ mL}}\cdot \frac{1000\text{ mL}}{1\text{ L}} = 0.018\text{ M}[/tex]

Therefore, the pH of the resulting solution is:
[tex]\displaystyle \begin{aligned}\text{pH} & = \text{p}K_a + \log\frac{[\text{Base}]}{[\text{Acid}]} \\ \\ & = (4.75) + \log \frac{(0.018)}{(0.024)} \\ \\ & = 4.75 + (-0.12) \\ \\ & = 4.63\end{aligned}[/tex]

In conclusion, the pH of the resulting solution is about 4.63.

plss help me with this I don't even know where to start to solve it

Answers

From the balanced equation of the reaction, the coefficients of the reactants and products are 1:2:1.

What is a balanced equation of a chemical reaction?

A balanced equation of a chemical reaction is an equation which balances the atoms of each element on the reactants as well as the products side of a chemical reaction.

The balanced equation of the reaction that occurs when magnesium bromide is heated is shown below:

[tex]MgBr_2 \rightarrow Br_2+Mg [/tex]

Therefore, the coefficients of the reactants and products are 1:2:1.

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